Escape system

ABSTRACT

A fire escape structure for multiple story buildings, including a series of fire resistive safety rooms which are located one above the other, and have floors containing escape openings through which a person may move downwardly from one room to the next lower room, with slides being provided beneath those openings along which a person may slide downwardly to a location near the floor of the next successive room. Draft stop doors are provided for closing the escape openings except when a person is moving downwardly therethrough, to prevent the development of an updraft through the rooms. These draft stop doors are preferably urged yieldingly to closed condition, to automatically close as soon as each person moves therepast.

United States Patent Nusslein Oct. 28, 1975 ESCAPE SYSTEM [76] Inventor: Karl F. Nusslein, 3014 Tillie St., Los Pnmary 8. i

Angeles, Calm 90065 Attorney, Agent, or F1rm 1 1am teen [22] Filed: Aug. 16, 1974 21 Appl. No.: 497,895 [571 ABSTRACT A fire escape structure for multiple story buildings, in- [52] US. Cl. 182/48 cluding a series of fire resistive safety rooms which are [51] Int. Cl. A62B l/20 located on abov th other, and have floors contain- [58] Field of Search 182/48, 49, 46, 47, 77; ing escape openings through which a person may 193/2 R, 2 C, 4, 12 move downwardly from one room to the next lower room, with slides being provided beneath those open- [56] References Cited ings along which a person may slide downwardly to a UNITED STATES PATENTS location near the floor of the next successive room. 287,880 11/1883 Small v 182/47 Draft. Stop doors are pmvded l clo.smg the escape 294,523 3,1884 stever 182,48 opemngs except when a person 15 moving downwardly 538,333 4/1895 Lemond.. 182/47 therethrough to prevent the development of an up- 1,194,098 8/1916 Viezzi 182/48 draft through t rooms- These draft p doors are 1,720,677 7/1929 l-lowlett 193/3 preferably urged yieldingly to closed condition, to au- 3,024,862 3/ 1962 Rishcoff 182/48 tomatically close as soon as each person moves there- 3,754,62l 8/1973 Liou 182/49 past FOREIGN PATENTS OR APPLICATIONS 12 Cl 8 D F 336,159 3/1904 France 182/48 aims 'awmg a i //d US. Patent Oct. 28, 1975 Sheet 1 of 2 3,915,258

U.S. Patent Oct. 28, 1975 Sheet 2 of2 3,915,258

ESCAPE SYSTEM BACKGROUND OF THE INVENTION This invention relates to improved fire escape structures for use in multiple story buildings. Certain features of the invention have been shown in Disclosure Document No. 028182 filed Feb. 6, 1974 in the [1.8. Patent Office.

Most multiple story buildings as now being constructed do not have fire escape facilities capable of effectively evacuating occupants from the upper floors of the building while a fire is in progress. During a fire, the elevators may become inoperative and useless as a means of escape, and in some instances the elevator shafts may actually function as fiues through which natural updrafts may propagate and spread the fire. Further, the internal stairways within a building, or any external fire escape stairs,do not permit rapid evacuation of the occupants and may become very crowded and be the source of injuries to persons going down the stairs. The stairwells, like the elevator shafts, may tend to enhance the development of updrafts and assist in spreading rather than deterring the fire, and may be taken over by firemen coming into and upwardly through the building to fight the fire. To overcome these disadvantages, there have been proposed and utilized in the past various types of fire escape slides, usually taking the from of tubes at the outside ofa building through which occupants may slide downwardly to ground level. However, these slides have not proven sufficiently practical for use on multiple story buildings, and as a result it is customary at present to rely upon elevators and stairs, in spite of their discussed inadequacy.

SUMMARY OF THE INVENTION A fire escape system embodying the present invention provides for protection of the occupants of each of the different floors of a multiple story building in a special safety room having fire resistive walls, and in addition allows for rapid evacuation of the protected occupants downwardly from each of these rooms to the ground level for complete escape from the building. To enable such downward evacuation, each of the rooms above a bottom one has a floor which contains an access opening through which persons may successively move downwardly to the next lower floor. Beneath each of these openings, the next lower room contains a slide, onto which the escaping persons move, and along which they then slide downwardly to a lower end of the slide near the floor of that particular room. A draft stop door is desirably provided at the location of each of the openings, to close the opening except when a person is moving downwardly therethrough, and thereby prevent development of updrafts between the rooms. These draft stop doors may be yieldingly urged to closed condition, preferably by a counterweight system, and may be defiectible downwardly to open condition by the weight of a user as he moves downwardly through one of the openings.

The walls of the individual safety rooms are desirably more fire resistive than other walls which are received between and define other rooms of the building. One

of the fire resistive walls of each safety room may conthen entering the escape room itself.

BRIEF DESCRIPTION OF THE DRAWING The above and other features and objects of the invention will be better understood from the following detailed description of the typical embodiments illustrated in the accompanying drawings in which:

FIG. 1 is a somewhat diagrammatic vertical sectional representation of a high rise building having a fire escape system constructed in accordance with the invention;

FIG. 2 is a fragmentary vertical section showing a portion of FIG. 1 on a larger scale;

FIG. 3 is a fragmentary horizontal section taken on line 3-3 of FIG. 2;

FIG..4 is an enlarged fragmentary vertical section through one of the escape openings and related equipment, taken on line 44 of FIG. 3i

FIG. 5 is a transverse vertical section taken on line 55 of FIG. 4;

FIG. 6 is an enlarged fragmentary vertical section taken on line 6 -6 of FIG. 3;

FIG. 7 is a view of one 'of the sliding doors taken on 77 of FIG. 3; and

FIG. 8 is a'view similar to FIG. 3, but showing a variational arrangement in which the safety rooms are added to the outside of the building and project outwardly beyond the sidewall of other adjacent portions of the building.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, there is illustrated fragmentarily a building 10 having a number of'storie s as shown, with safety rooms lla, llb, llc, etc., provided on thedifferent floors respectively and at locations directly above and in vertical alignment with one another. As seen best in FIG. 3, typically illustrating room 11, each of these safety rooms is preferably rectangular in horizontal section, desirably being defined at one side by a vertical wall 12 at the outside of the building, and at its opposite side by a parallel vertical inner wall 13. Two walls 14 and 15 extend inwardly from and perpendicular to wall 12 to connect to the opposite ends of the inner wall 13. Spaced inwardly from and parallel to wall 13, there is desirably another vertical wall 16, defining with wall 13 a protected hallway 17. This wall 16 may form one side of a corridor 18 of the building, whose opposite side is defined by a wall 19, containing doorways 20 leading into various rooms 21, 22, 23, etc. Additional rooms may be provided at 24 and 25 at opposite sides of the safety room 110.

The walls, '12, 13, 14 and 15 enclosingand forming safety room 110, as well the additional protective wall 16, are all formed of a highly heat insulative, fire proof material, which is considerably more resistive to the conductance of heat therethrough than is wall 19 or any of the other walls 26, 27, etc., which form other rooms of the building and segregate other spaces on the same story. FIG. 6 illustrates a preferred construction for the walls 12, 13, and 14, 15 and 16, each of which may as shown be formed of a number of parallel wall boards 28 of asbestos, asbestos cement, or the like,

spaced apart to form air layers 29 therebetween, and preferably with sheet metal skins 128 and/or lath and plaster or other covering material, at opposite sides of the wall. As a result, any occupants of the building who are able to reach the interior of safety room 11c, or any of the other safety rooms on the other stories, are effectively protected by the heat insulative walls from the fire, and will remain so protected for a relatively long period of time enabling full evacuation of the building.

Near the opposite ends of hallway 17, the wall 13 of the safety room contains two doorway openings 30 and 31, which are typically rectangular and adapted to be closed by two sliding doors 32 and 33. As seen in FIG. 7, each of these doors 32 and 33 may be suspended by rollers 34 riding on a track 35 attached to wall 13, to mount the doors for sliding movement between their open broken-line positions of FIG. 3 and their closed full-line of that figure. Doors 32 are yieldingly urged to their closed positions, to normally return to those closed positions except when purposely opened by a person entering or leaving the safety room. This automatic return of the doors may be achieved in optimum fashion, and with maximum reliability, by merely mounting the tracks to have a slight inclination (FIG. 7) with respect to the true horizontal, and in a direction causing the doors to move by gravity to their closed positions.

Extending across the opposite ends of hallway 17, there are provided two short walls 36 and 37 forming continuations of and having the same heat resistive characteristics as the two walls 14 and respectively. These walls 36 and 37 contain rectangular doorway apertures 38 and 39, which are closed by a second pair of sliding doors 40 and 41, mounted by tracks 42 for sliding movement between their broken-line open positions and full-line closed positions of FIG. 3. As in the case of doors 32 and 33, the doors 40 and 41 are yieldingly urged to their closed positions, as by giving tracks 42 a slight inclination as illustrated in FIG. 7. All of the doors 32, 33, 40 and 41 are of highly heat insulative material, preferably having the same heat insulative characteristics as the walls l2, l3, 14, etc., and are of course considerably more heat insulative and fire resistive than the normal doors provided at other locations in the building.

Persons may have access to the entrance doorways 38 and 39 through a pair of short corridors 43 and 44 extending from the main corridor l8 and along the opposite sides of the safety room 110.

Returning again to FIGS. 1 and 2, each of the various safety rooms 110, llb, 1 la, etc. has a horizontal floor 45 defining the bottom of the room and also serving as the ceiling of the next lower room. Preferably no false ceiling or upper duct work or the like is provided in the safety rooms, and the side walls 12, 13, 14, 15 and 16 all extend the full vertical distance between successive floors 45. Similarly, the walls 36 and 37 together with their doors 40 and 41 close the entire space vertically between successive floors 45, so that when the four doors are closed the interior of each room 11a, 11b, etc., is entirely closed off from the rest of the building except insofar as access may be had between the safety rooms themselves, as will be discussed hereinbelow. The floors 45 may be formed of concrete, and should have fire insulative capabilities corresponding to the various walls l2, 13, etc.

Each of the floor 45 above the first story contains an escape opening 46 (FIGS. 2, 3, 4 and 5), which extends vertically through the horizontal floor, and through which a person may advance downwardly from one of the safety rooms to the next lower safety room. As seen in FIG. 3, each of the escape openings 46 may be rectangular in horizontal section, and is sufficiently large to easily pass a person downwardly therethrough, preferably being between about 2 and 3 feet wide, (desirably 30 inches) and between about 3 and 6 feet in length, (desirably 48 inches). Each opening may be defined by an essentially rectangular frame 146, typically formed of heavy guage metal or the like, and having a peripheral flange 246 at its upper edge secured to the floor.

Beneath each of the escape openings 46, there is provided within the next lower safety room a slide 47 or 47a, along which a person may slide downwardly from the location of the opening 46 to the discharge end 48 of the slide received near the floor 45 of the safety room. These slides 47 and 47a may be of any convenient construction to present an inclined slide surface along which a person may slide downwardly by gravity. In instances in which the height of a particular story of the building is greater than normal, as for instance in the bottom story of FIGS. 1 and 2, the slide may be of spiral configuration, as shown, having an upper portion received beneath the associated opening 46, and then spiraling downwardly about a vertical axis 49 to a location near the ground floor level, in a manner providing an optimum slide inclination at all locations without danger of attaining an excessive sliding speed. The other slides 47 above the bottom story of FIGS. 1 and 2 are illustrated as simple, straight, non-spiraling slides, which through the major portion of their vertical extents are inclined at a predetermined fairly abrupt angle a to the horizontal, and which gradually curve to extend more horizontally at their lower ends 48. The upper extremity 50 of each slide may be located closely adjacent one edge of the associated opening 46, with an inclined surface 51 desirably being provided on the frame 146 at that edge of the opening and at the same inclination as the slide to present an essentially continuous slide surface to a user. At that side of the opening 46, and adjacent slide surface 51, the upper surface of floor 45 provides an upwardly facing seat surface area 52 of a size sufficient to enable a person to sit on this area of the floor while his legs hang downwardly through opening 46 and onto the upper portion of the slide, so that he may then move forwardly onto the inclined surface 51 and slide downwardly therealong and along the inclined upper surface 53 of the slide to its lower end. Extending along the other three sides of the rectangular opening 46, there is provided a handrail or handhold structure 54, which may consist of a tube, pipe, or the like connected at its opposite ends 55 to the floor, and extending upwardly from those ends at an inclination at 56 and then horizontally along opposite sides of the opening 46 at 57, and then having a cross piece portion 58 extending across the second shorter side of opening 46. At the corner locations 59, this generally U-shaped handrail may be supported from the floor by two legs 60.

To prevent updrafts through each of the escape openings 46, there is provided in conjunction with each such opening a draft stop door 61, which may be formed of an appropriate rigid material capable of withstanding high temperatures, such as heavy guage stainless steel or a heat insulative substance, and which is essentially flat and in the full-line closed position of FIG. 4 has a rectangular horizontal outline configuration just slightly larger than that of opening 46, to project laterally a short distance beyond each of three sides of the associated opening 46 and assure closure thereof. At the fourth side of opening 46, the fourth edge of the draft stop door 61 is connected by a hinge 62 to the frame 146 of the associated floor structure 45 to swing downwardly between the upper full-line closed position of FIG. 4 and the downwardly deflected open broken-line position of that figure. An arm 63 is connected rigidly to door 61 to swing therewith about the horizontal axis 64 of hinge 62, and carries a counterweight 65, which in the closed position of door 61 hangs downwardly as illustrated in FIG. 4, so that the weight normally tends to return the door to its closed position of extension across the underside of escape opening 46. Arm 63 may extend through a slot or notch 66 formed in the upper central portion of the slide (FIG. 5), to allow the desired swinging movement of the counterweight and arm. In its downardly deflected open position shown in broken-lines in FIG; 4, the door 61 is received adjacent and engages, and forms in effect a portion or continuation of, the inclined slide surface 53 of slide 47. Rails 67 may be provided at opposite sides of that slide surface 53 to retain a person on the slide as he moves downwardly.

Each of the rooms 11a, 1 lb, etc. may contain an appropriate electrically energized light 67 (FIGS. 1 and 2), with all of these lights desirably being energized by wires 68 which are enclosed completely within the heat resistive safety rooms 11a, 1 lb, Ilc, etc. and do not extend into the other unprotected rooms of the building. This wiring may extend downwardly through all of the safety rooms and ultimately extend to the outside of the building from the bottom of these rooms, as at the location 69 of FIG. 1. Also, a door 70 through the outside wall of bottom safety room lla may allow final escape of the occupants from that bottom room to the outside of the building,'with this door preferably having a lock pin normally maintained closed and releasable only from the inside of the room. All of the rooms may also contain loudspeakers represented at 71, fed by wiring 72 extending only through the safety rooms, as discussed in connection with wiring 68, and extending to the outside of the building through the outer wall of bottom room lla, as at 73, and then connecting to an amplifier and microphone system at the outside of the building so that firemen can give instructions to persons within the safety rooms during a fire.

To now describe the manner of use of the fire escape system illustrated in FIGS. 1 through 7, assume that a fire occurs in one or more of the upper stories of the building of FIGS. 1 and 2, and that the fire spreads sufficiently rapidly that it becomes desirable to evacuate the building. On each of the floors, the occupants walk from their respective individual rooms along corridor l8 and one of the branch corridors 43 or 44 to the location of one of the doors 40 or 41, and then open that door, walk into the protected inner hallway 17, open one of the doors 32 and 33, and walk into the protected safety room 11c (or other similar safety room on another of the floors). The heat resistive characteristics of the walls of the safety rooms prevent injury to the occupants while contained within those safety rooms, and even though the fire may spread to the outer sides of the walls l4, l5 and 16. After each occupant enters the safety room on his particular floor, he walks to the entrance side of the escape opening 46 in that room (right side in FIG. 3), and sits down on the seat surface 52 ad- 5 jacent that opening. While sitting on this surface, he allows his legs to fall downwardly through the opening 46 and thereby opens the draft stop door 61, so that the user may then pull himself forwardly onto the slide by grasping handrail 54 to then slide downwardly along the slide to the next lower floor. As soon as each person has moved downwardly past the location of the draft stop door 61, this door automatically returns upwardly to its closed position, under the influence of the counterweight 65, to prevent the development of any continuous draft upwardly through the rooms,.and thus mimimize the danger of development of a fire within the safety rooms. By virtue of the speed with which the occupants can slide downwardly from one room to the next, through as many rooms as are necessary to ultimately reach bottom room Ila and then exit past door 70, the'entire building can be evacuated very rapidly and with maximum protection of the occupants.

FIG. 8 is a horizontal sectional view similar to FIG. 3, but showing a variational arrangement in which the safety rooms 74, corresponding to rooms 1 la, 1 lb, etc., of FIGS. 1 to 7, are added to an existing building and project outwardly beyond the plane of the outer wall 75 of that building. The escape openings 76, slides 77, draft stop doors 78, sliding doors 79, and the walls and floor structures, may all be the same as in FIGS. 1 to 7,'with the safety rooms being accessible in any convenient manner, as by corridors represented at and 81. The use of the rooms of FIG. 8 may be the same as that described in connection with the first form of the invention.

While certain specific embodiments of the present invention have been disclosed as typical, theinvention is of course not limited to these particular'forms, but rather is applicable broadly to all such variations as fall within the scope of the appended claims.

I claim:

1. In a building having a plurality of stories, a fire escape comprising: v I

a series of safety rooms on different stories respectively of said building and having walls which are more fire resistant than most of the other walls of said building to prevent thespread of fire into said rooms;

said rooms having essentially horizontal floors between vertically successive ones of said safety rooms and each extending across the bottom of one safety room and the top of the next successive safety room;

each of said floors containing an escapeopening extending downwardly through said floor from one of said safety rooms on an upper one of said stories to the next successive safety room on the next lower story to enable escape of a person downwardly between said rooms;

a plurality of slides in different ones of said rooms respectively on different floors of the building, each of said slides having an upper end positioned to receive a person moving downwardly through one of said openings in the floor of one of said safety rooms, and having an inclined surface along which said person may slide downwardly to a lower end of the slide near the floor of the next lower safety room; 7

a plurality of draft stop doors operable to close said openings in said floors of the different safety rooms to prevent the creation of updrafts therethrough and deflectible downwardly from upper closed positions of extension across said openings to lower opened positions to pass persons downwardly onto said slides; and

means yieldingly urging said draft stop doors upwardly.to said closed positions. A

2. A fireescape as recited in claim 1, in which said draft stop doors are positioned in the path of movement of a person onto said slides and adapted to be opened by such movement of a person onto the slides.

3. A fire escape as recited in claim 1, in which said draft stop doors in said opened positions are received adjacent and inclined in correspondence with an upper portion of said inclined surface of the slide.

4. A fire escape as recited in claim 1, in which said means are counterweight means yieldingly urging said doors to closed position.

5. A fire escape as recited in claim 1, including handrail structures in said safety rooms at opposite sides of said openings and projecting upwardly thereabove.'

6. A fire escape as recited in claim 1, including essentially U-shaped handrail structures in said safety rooms mounted to and spaced upwardly above said floors and extending about three sides of said openings but leaving a fourth side unobstructed for movement of a person downwardly into and through said openings.

7. A fire-escape as recited in claim 1, in which there are seat surfaces on said floors adjacent said openings and on which a person may sit with his legs extending downwardly into one of said openings, and from which a person may then move horizontally into the opening and downwardly onto a slide.

8. A fire escape as recited in claim 1, in which said fire resistant walls of said safety rooms contain doorway openings through which a person may walk into any particular safety room from other rooms on the same floor, there being fire resistant doors for closing said doorway openings.

9. A fire escape as recited in claim 1, in which said fire resistant walls of an individual one of the safety rooms include an access wall containing at least one doorway opening into. which a person may walk from other rooms on the same floor, there being a fire resistant door for said doorway opening, and an additional vertical fire resistant wall spaced from said access wall and extending essentially parallel thereto at a location opposite and extending past said doorway opening to define a protected entrance hallway through which said doorway is accessible.

10. A fire escape as recited in claim 9, including two fire resistant doors closing off opposite ends of said hallway. v

1 l. A fire escape as recitedin claim 1, in which a bottom one of said safety rooms has a higher ceiling than other upper safety rooms, one of said slides being located within said bottom room and being of spiral con-.

figuration. I

12. A fire escape as recited in claim 1, in which said fire resistant walls of individual ones of said safetyrooms include two parallel side walls and an access wall extending therebetween and facing inwardly of the building and containing at least one doorway, there being an additional fire resistant wall spaced inwardly from and extending essentially parallel to said access wall and having a portion opposite said doorway and defining with said access wall a protected entrance hallway through which persons may walk into the safety room, means forming doorways at opposite ends of said hallway, three sliding fire resistant doors closing said three doorways and yieldingly urged-toward closed po sitions, handrails projecting upwardly from said floors of the safety rooms adjacent said openings but leaving said openings accessible from one side for movement of a person into the opening, said floors having seat areas adjacent said openings at said accessible side thereof and on which a person may sit with his legs hanging downwardly into an opening prior to movement downwardly through the opening and onto a slide, and hinges mounting each of said doors for swinging movement about essentially horizontal axes between an upper essentially horizontally extending closed position of extension across the underside of one of said openings and a downwardly deflected open position of reception against and inclination in correspondence with an upper portion of said inclined surface of the associated slide, said means including a counterweight yieldingly urging each of said draft stop doors to its upper closed position. 

1. In a building having a plurality of stories, a fire escape comprising: a series of safety rooms on different stories respectively of said building and having walls which are more fire resistant than most of the other walls of said building to prevent the spread of fire into said rooms; said rooms having essentially horizontal floors between vertically successive ones of said safety rooms and each extending across the bottom of one safety room and the top of the next successive safety room; each of said floors containing an escape opening extending downwardly through said floor from one of said safety rooms on an upper one of said stories to the next successive safety room on the next lower story to enable escape of a person downwardly between said rooms; a plurality of slides in different ones of said rooms respectively on different floors of the building, each of said slides having an upper end positioned to receive a person moving downwardly through one of said openings in the floor of one of said safety rooms, and having an inclined surface along which said person may slide downwardly to a lower end of the slide near the floor of the next lower safety room; a plurality of draft stop doors operable to close said openings in said floors of the different safety rooms to prevent the creation of updrafts therethrough and deflectible downwardly from upper closed positions of extension across said openings to lower opened positions to pass persons downwardly onto said slides; and means yieldingly urging said draft stop doors upwardly to said closed positions.
 2. A fire escape as recited in claim 1, in which said draft stop doors are positioned in the path of movement of a person onto said slides and adapted to be opened by such movement of a person onto the slides.
 3. A fire escape as recited in claim 1, in which said draft stop doors in said opened positions are received adjacent and inclined in correspondence with an upper portion of said inclined surface of the slide.
 4. A fire escape as recited in claim 1, in which said means are counterweight means yieldingly urging said doors to closed position.
 5. A fire escape as recited in claim 1, including handrail structures in said safety rooms at opposite sides of said openings and projecting upwardly thereabove.
 6. A fire escape as recited in claim 1, including essentially U-shaped handrail structures in said safety rooms mounted to and spaced upwardly above said floors and extending about three sides of said openings but leaving a fourth side unobstructed for movement of a person downwardly into and through said openings.
 7. A fire escape as recited in claim 1, in which there are seat surfaces on said floors adjacent said openings and on which a person may sit with his legs extending downwardly into one of said openings, and from which a person may then move horizontally into the opening and downwardly onto a slide.
 8. A fire escape as recited in claim 1, in which said fire resistant walls of said safety rooms contain doorway openings through which a person may walk into any particular safety room from other rooms on the same floor, there Being fire resistant doors for closing said doorway openings.
 9. A fire escape as recited in claim 1, in which said fire resistant walls of an individual one of the safety rooms include an access wall containing at least one doorway opening into which a person may walk from other rooms on the same floor, there being a fire resistant door for said doorway opening, and an additional vertical fire resistant wall spaced from said access wall and extending essentially parallel thereto at a location opposite and extending past said doorway opening to define a protected entrance hallway through which said doorway is accessible.
 10. A fire escape as recited in claim 9, including two fire resistant doors closing off opposite ends of said hallway.
 11. A fire escape as recited in claim 1, in which a bottom one of said safety rooms has a higher ceiling than other upper safety rooms, one of said slides being located within said bottom room and being of spiral configuration.
 12. A fire escape as recited in claim 1, in which said fire resistant walls of individual ones of said safety rooms include two parallel side walls and an access wall extending therebetween and facing inwardly of the building and containing at least one doorway, there being an additional fire resistant wall spaced inwardly from and extending essentially parallel to said access wall and having a portion opposite said doorway and defining with said access wall a protected entrance hallway through which persons may walk into the safety room, means forming doorways at opposite ends of said hallway, three sliding fire resistant doors closing said three doorways and yieldingly urged toward closed positions, handrails projecting upwardly from said floors of the safety rooms adjacent said openings but leaving said openings accessible from one side for movement of a person into the opening, said floors having seat areas adjacent said openings at said accessible side thereof and on which a person may sit with his legs hanging downwardly into an opening prior to movement downwardly through the opening and onto a slide, and hinges mounting each of said doors for swinging movement about essentially horizontal axes between an upper essentially horizontally extending closed position of extension across the underside of one of said openings and a downwardly deflected open position of reception against and inclination in correspondence with an upper portion of said inclined surface of the associated slide, said means including a counterweight yieldingly urging each of said draft stop doors to its upper closed position. 